Then, around seven weeks postpartum, Stone had the first of what are called intrusive thoughts -- frightening notions about what could happen to you or someone else in your life. She thought about smothering her son with a burp cloth.

She reached out for help about a month later, not because she thought she could get better if she got treatment; she just wanted the pain to go away.

"I'm not insane?"

"I thought they would cart me off either to jail or a mental institution," said Stone. "I really thought when I told the therapist that I met with for the first time about my intrusive thoughts that she was going to pick up the phone right then and dial 911. And she goes, 'Well those are intrusive thoughts, and this is what that is, and it's very common.'"

"I'm not insane?" Stone thought,with relief.

She was diagnosed with postpartum depression and anxiety and was treated through therapy and medication.

The spectrum of illnesses goes beyond depression, which people don't realize, said Stone. Moms could be suffering from a range of mood and anxiety disorders; in the most rare and serious cases, impacting only 0.2% of all moms, they suffer from psychosis, the disorder that often garners the painful national headlines.

In the vast majority of cases, women with perinatal mental illness won't ever physically harm themselves or their children.

The birth of a mission

As for Stone, it took many months before she felt like herself again.

When she returned to her corporate marketing job, she'd go into the bathroom and just sit in a stall, she said. She'd think, "I don't know what I'm doing. I don't know who I am. I don't know where I am. I don't know what's going on."

Even after she got better, she felt alone and somewhat angry. How could a fairly educated woman like herself not know anything about intrusive thoughts or how postpartum mental illness could include anxiety disorders?

Ten years later, Katherine Stone and her blog, Postpartum Progress, are considered one of the leading sources of information and support for moms suffering from some form of perinatal mental illness. The blog, which half a million women access annually, has also led to the creation of a nonprofit with the same name focused on raising awareness, pushing for more scientific research on causes and treatments and improving screening for the disease.

"People always think you have a master plan and honestly, even from the start with the first blog post, there was never a master plan," said Stone, whom I interviewed last year and again this year for this story. "The focus was always on what can be done to help other moms so they're not alone."

'Climb Out of the Darkness'

To help raise money for the nonprofit, last year one of Postpartum Progress' board members suggested holding an event on the longest day of the year, the first day of summer, to shine the most light on the issue. Four weeks later, the first annual "Climb Out of the Darkness" was held, with 177 people from around the world climbing mountains, hiking and walking along beaches to raise $40,000 from family, friends and other loved ones.

Katherine Stone and her fellow participants after their climb in Atlanta in June.

This year, the event grew exponentially, with 1,600 climbers from 41 states and nine countries, including England, Switzerland, Mexico, Malaysia, South Africa and Australia, raising a total of $165,000, quadruple the amount raised the year before. It has become the largest event in the world raising awareness of maternal mental illness, according to Postpartum Progress.

"For many of these women, it's the first time they've ever told their story. It's the first time they've asked people to support by donating money," said Stone, adding that many of the climbers have been interviewed by local television stations and newspapers. "They're all having absolute heart attacks with me ahead of time, and I keep reminding them (to) keep focused on the fact that there's a woman in the audience who needs to hear what you have to say."

Raivon Lee has only recently started speaking out about her postpartum depression and anxiety.

One of those first-time climbers this year was Raivon Lee, a mom of a 17-month-old, who cried every day for months after her son was born. In her email to family and friends asking for support as she planned to climb an Atlanta-area mountain, she revealed how at the lowest point of her postpartum depression and anxiety, "the thought of death was actually a peaceful thought."

"It's really a very scary place to be, and I really don't think people get it, but I don't think I got it before it happened to me," said Lee, who worked as a nurse before becoming a mom. "If I can just help one mom feel a little bit better or just get help, then it makes me so extremely happy."

Lesley Neadel, who is pregnant, knows she could very well suffer postpartum depression and anxiety again.

Lesley Neadel of Hoboken, New Jersey, climbed for the second time this year. She suffered from severe postpartum depression and anxiety when her daughter was born three and a half years ago, and is now six months pregnant with her second child. She knows she could battle depression and anxiety again.

"I'm focusing on how good I feel now and that if I find myself feeling badly again, I have support systems at the ready at this point," she said.

One of those support systems includes Postpartum Progress, which she said she came across when she was searching online, trying to find a community of women who might understand what she was going through.

"I found Postpartum Progress and suddenly was reading exactly my symptoms and stories of women who had been through what I had, who had it worse than I had," said Neadel, a public relations executive in New York City. "Just finding that community, knowing you're not alone has been unbelievable."

Much more progress needed

CNN's Kelly Wallace, a mom of two, knew about postpartum depression but only from news stories she covered.

While Stone believes there is more awareness today than when she started what has become a mission ten years ago, and that women are finding a safe place to connect with other women who know exactly what they're going through, she still believes there is a lot more work to do.

She still hears stories from women who said their doctors told them they were suffering from the baby blues, which would eventually go away, or not to take medication because it could shrink their brains or who told them they were fine as long as they didn't want to kill themselves or their baby.

Women are still "getting treated horribly, there's still stigma, they're still not getting the right kind of help," said Stone.

Only 15% of those who ever get a perinatal mood or anxiety disorder get treated, which means that the 85% who don't get treatment could have chronic mental illness throughout their lives, dramatically impacting the mental health of their children, according to a report by Harvard University's Center on the Developing Child.

Stone wants to see more research into the underlying causes of the illness and the development of more targeted treatments, with the goal of one day being able to identify women ahead of time who are most at risk.

Additional and improved screening are also needed, she said. Many women say no one ever talked with them about depression or mood and anxiety disorders while they were pregnant or after giving birth.

The only reason I knew about the illnesses and was on the lookout for any signs during my two pregnancies and after my deliveries was because of news stories I had reported. I don't remember reading about them in any of the pregnancy prep books and don't recall my OB/GYN or pediatrician ever asking me about them either.

Today the most common screening is a questionnaire to try and assess how a new mom feels about herself and her baby called the Edinburgh Postnatal Depression Scale. New mothers are asked to answer questions such as whether they have been anxious or worried for no good reason, if they have had difficulty sleeping, if they are feeling sad and miserable and if the thought of harming themselves had ever occurred to them.

One of the issues, said Stone, is that the questionnaire, if given out at all, is often given to women soonafter childbirth when a new mom has a hard time focusing on just about anything, let alone being able to reflect on whether her feelings at that moment are out of the ordinary.

Motivation from the women

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What keeps Stone going, even when she feels anxious about how much her blog and nonprofit have grown, are the emails and comments she gets from women: comments like "It wasn't until I read this that I knew what was going on" or "I thought I was a horrible mother" or "I've just called my doctor."

"When I realize that what we're doing is not only raising awareness but facilitating people into treatment, that we are convincing them that it's okay to call and ask for help, I (know) we've hit on something," she said.

When women started writing and asking if they could tattoo the logo of Postpartum Progress, an image of what Stone calls a "warrior mom," she could not quite believe it.

Stone is feisty and passionate about helping women who are suffering or have suffered from a perinatal mental illness, saying she would throw herself on a fire or in front of a bus to help moms. But when she talks about her daughter Madden, who is now 8, the emotions break through her steely resolve.

"When she has a baby, if she has a baby, she's not going through what all these women go through right now," said Stone, fighting back tears as she recounted the suffering of women, including her own mother and grandmother, who have experienced depressive episodes around pregnancy and hated themselves for it.

"My daughter's every daughter. Every mom out there should be concerned about this."